The ability of computer users to access programs and share data through local area networks (LANs) has become a readily expected part of most working environments. The improved efficiency within a particular LAN environment is often enhanced with the convenience of remotely accessing the LAN. An important extension to LANs is the provision of a wireless LAN (WLAN).
In a WLAN, end station units suitably employ radio communication using an FCC allotted frequency band of, for example, 2390 MHz (megaHertz) to fulfill performance expectations of wired LANs but without costly wire installation. One example of a WLAN is illustrated in FIG. 1. As shown, three end station units 10, 12, and 14 are in range with one another and have formed a portion of a WLAN 16. Also included in WLAN 16 is an access point station 18 that can access both connection oriented and connection-less services. Access point station 18 thus may support connection to both a local Ethernet backbone and some form of telecommunication transport, such as ISDN, ATM, or T1, as is well appreciated by those skilled in the art.
With the inclusion of connection oriented stations within a WLAN, the connection oriented services provide a potential mechanism for reserving bandwidth, such as for real-time or time-bounded data transfers, which may require a high data transfer rate. The connection-less services suitably provide typical asynchronous access to the media in an fashion similar to Ethernet. Potential contention among varying unit types for communication in the WLAN raises significant issues for consideration in the development of standards for the WLAN.
The rules for communication in the 2390 MHz radio band for WLANs provide an etiquette for media access by end stations. In a simple transmission, a packet is sent from an end station to another, e.g., from end station 10 to end station 12, and the media is then allowed to return to a quiet/idle state. The etiquette requires that at least 50 microseconds (.mu.s) of silence follows the packet transmission before another end station can utilize the media and transmit data. If an end station senses that the media is busy, it must pick a random backoff time and wait that period before attempting to access the media again. If the media is again busy, the end station must backoff and wait twice as long as the first backoff time before trying to access the media. The backoff doubling then continues until the length of the period exceeds 10 millisecond (ms), which can significantly reduce the efficiency of transmitting data in the network.
Accordingly, a need exists for a technique to achieve greater throughput with more efficient data transmission in a WLAN.